6+ days of battery and Water-resistant up to 50m Compatible with iOS 15 or higher & Android OS 9.0 or higher Live healthier: all-day stress detection with cEDA and daily Stress Management Score, ECG app for atrial fibrillation assessment, irregular heart rhythm notifications, SpO2, health metrics dashboard, menstrual health tracking and mindfulness content Measure and improve sleep quality: personalized Sleep Profile, daily Sleep Stages and Sleep Score, Smart wake alarm and do not disturb mode Enhance activity: 24/7 heart rate monitoring, built-in GPS and workout intensity map, Daily Readiness Score, Active Zone Minutes, all-day activity tracking, 40+ exercise modes and automatic exercise tracking Designed for all-day wear: on-wrist Bluetooth calls, texts, phone notifications, customisable clock faces, iOS and Android compatible, sleek, slim and water resistant to 50 meters, 6+ day battery and fast charge Includes 6-month Premium membership for deeper insights and guidance, exclusive workouts, mindfulness sessions and more Included in box: Fitbit Sense 2 Smartwatch (Size Small and Large Straps included). Wrist straps measure small 140 mm–180 mm with additional Large 180 mm–220 mm. Charger also included (compatible with other Fitbit Smartwatches)